1. Field of the Disclosure
The present invention relates generally to methods and apparatus for gripping and manipulating pipe. More particularly, the present invention relates to systems and methods for facilitating the connection and disconnection of sections of drill pipe.
2. Background Information
Drill strings used in rotary drilling operations for the recovery of hydrocarbons are often constructed from individual lengths of drill pipe connected end-to-end to form a drill string. The individual lengths of drill pipe are typically joined by threaded connections. Because of the loads incurred by the drill string, the connections have to be pre-loaded with a certain amount of torque in order to maintain a satisfactory connection during use.
Pipe tongs are one tool used for facilitating the connection and disconnection, or making and breaking, of drill pipe connections. Pipe tongs are generally located at the drill floor and operate by gripping a connection between two adjacent lengths of pipe and applying torque to loosen or tighten the connection. Many pipe tongs operate by gripping above and below the junction between two adjacent pipe sections. The tongs then rotate the two sections of pipe relative to each other.
To make or break a connection between two pipes, more than one revolution of the two sections of pipe relative to each other is required. Multiple revolutions can be achieved by repeated twisting and releasing one of the tubulars or by multiple rotations without releasing grip from the tubular, depending on the system design. Repeated engagement, rotation, and release to achieve the desired number of revolutions requires multiple steps, which may be time consuming. In addition, achieving multiple rotations without releasing grip using hydraulically actuated tongs requires the use of a rotating hydraulic coupling, which represents a potential point of failure and/or safety concern. In cases where multiple rotations without releasing grip are driven by co-mounted electric motors, the use of commutator rings and bushings provide a relatively bulky rotating assembly that may present safety and maintenance issues.
Accordingly, there remains a need in the art for systems and methods for facilitating the connection and disconnection of pipe sections, which overcome some of the foregoing difficulties while providing more advantageous overall results.